Global Warming : Melting Glaciers
By Aakriti Bansal & Ajay Partap Singh
Global warming is the increase in the average measured temperature
of the earth near surface, air and oceans since the mid 20th Century
and it's projected to continuation. Natural phenomenon such as solar
variation combined with volcanoes probably had a small warming effect
from pre-industrial times. These basic conclusions have been endorsed
by at least 30 scientific societies and academies of science including
all of the national academies of science of the major industrialized
countries
The term Global warming refers to the warming in recent decades, its hazardous
continuation and its harmful human influence.
At present, the atmospheric concentration of CO2 is about 385 ppm (parts per
million) by volume. But, the future CO2 levels are expected to rise due to ongoing
burning of fossil fuels. Fossil fuel reserves are sufficient to reach 970 ppm
and continue emission past 2100. If coal, tar, sand or methane clatherates are
extensively used.
The affects of forcing agents on the climate are complicated by various feedback processes. One of the most pronounced feedback effects relates to the evaporation of water warming by the addition of long-lived Green house gases such as CO2 will cause more water to evaporate into the atmosphere. CO2 does not dissipate, if stays in the atmosphere for five decades or more causing the earth's temperature to rise. Which means that the CO2 produced in 1960s, 1940s, 1950s is still present in atmosphere till date. To stablize the planet's climate by the end of century we need 70% reduction in CO2 emission below 1990 levels by 2050.
Since water vapor itself acts as green-house gas, the atmosphere warms further;
this warming causes more water vapour to evaporate and so on until the other
processes stop the feedback loop. The result is much larger green-house effect.
So the goal should be to stabilize CO2 at 450 ppm by year 2050.
Feedback due to clouds is an ongoing effect. Whether the net effect is warming
or cooling depends upon details such as the type and altitude of the cloud. These
details are difficult to represent in climate models in part because clouds are
much smaller than the spacing between points on computational grids of climate.
With global temperature increasing, the ice at the Poles melt at an amazing rate.
Which is a sign of danger.
A different hypothesis is that variation in the Solar output is possibly amplified by cloud seeding via galactic cosmic rays that might influence the generation of clouds condensation nuclei and thereby affect the climate.
Ozone depletion, the steady decline in the total amount of ozone in earth's stratasphere is frequent cited in relation to global warming. Although there are areas of linkage, the relationship between two is not strong.
Due to these reasons the earth has warmed in the past century and we are now
seeing dramatic effect. Oceans are rising, coral reefs are dying, species are
disappearing and glaciers are melting.
There is a dire need of awareness to the people. |
